This proposal details a 5-year training program to develop the skills necessary to pursue independent research in basic science as part of a career in academic medicine. The principal investigator is a board-certified pediatrician, trained in pediatric cardiology, currently holding a tenure-track faculty appointment at the University of Pittsburgh with a minimum of 75% protected time for research. This training program centers upon studies of cardiac cellular physiology as it relates to fetal and neonatal cardiac glutamate metabolism. Dr. Ian Reynolds will mentor the principal investigator's training. He is a well-established investigator in the field of mitochondrial biology. Dr. Bradley Keller, a highly regarded researcher in cardiac development, will act as co-sponsor. Both have extensive experience in training individuals who have gone on to successful research careers and the combination of their skills and interests will provide comprehensive support of the applicant's research efforts. Dr. Ralphe's research will investigate the role of glutamate transport by the excitatory amino acid transporters (EAATs) in the heart. His preliminary data has demonstrated the presence of EAAT1, EAAT2, and EAAT3 in cardiomyocytes, with EAAT1 localizing to the inner mitochondrial membrane. Understanding the mechanisms of glutamate transport in the heart has important implications in the management of children with cyanotic congenital heart defects and all patients undergoing cardiopulmonary bypass. Three specific aims will be addressed: 1) the demonstration of localization of EAAT1, EAAT2, EAAT3 and EAAT4 in the cardiomyocyte; 2) the definition of the functional roles played by EAAT1 and EAAT4 within the mitochondria; and 3) the provision of direct evidence that EAAT2 and EAAT3 mediate glutamate uptake into the cardiomyocyte. The University of Pittsburgh and the Children's Hospital of Pittsburgh provide an ideal setting in which to undertake this proposal due to the strong research environment and the availability of outstanding mentors and advisors who will remain closely involved throughout the tenure of this program. This combination will maximize the potential for the principal investigator to develop into a successful independent research scientist.